A US father-son pair accused of helping former Nissan boss Carlos Ghosn in his audacious escape from Japan arrived in Tokyo on Tuesday after losing their battle against extradition.

An Istanbul court on Wednesday sentenced three Turks to four years and two months in prison for helping smuggle former Nissan boss Carlos Ghosn in a musical instrument case from Lebanon to Japan.

Japanese auto maker Nissan said Monday it is not in talks with Apple to develop self-driving cars, a week after Hyundai also denied reports it was discussing the top-secret project with the US tech giant.

A whistleblower at Nissan told a Tokyo court on Thursday he had been instructed to find ways of boosting the retirement benefits of the fugitive former chairman Carlos Ghosn.

Proceedings in a $95 million lawsuit brought by Japanese car giant Nissan against its former chairman Carlos Ghosn began Friday in a court near Tokyo.

Fugitive auto tycoon Carlos Ghosn made his first public appearance in months Tuesday to launch a business programme at a Lebanese university.

Greg Kelly, a former aide to ex-Nissan chief Carlos Ghosn, pleaded not guilty on Tuesday to allegations of financial misconduct as his trial began in Tokyo.

The trial opened in Turkey on Friday of seven suspects over the audacious escape of former Nissan chief Carlos Ghosn from Japan to Lebanon via Istanbul in December, local media reported.

Japanese prosecutors said Thursday they would seek the extradition of a former special forces soldier and his son, arrested in the United States and accused of helping fugitive former Nissan chief Carlos Ghosn jump bail and flee Japan.

Japanese car giant Nissan on Wednesday filed a civil lawsuit to reclaim some 10 billion yen ($90 million) from former chairman Carlos Ghosn for what it called "years of his misconduct and fraudulent activity".

Japanese authorities on Thursday issued arrest warrants for a former U.S. Special Forces soldier and two other men on suspicion of smuggling former Nissan Motor Co boss Carlos Ghosn out of Japan.

Nissan is "in no way" planning to end its partnership with Renault, the Japanese auto giant insisted on Tuesday after a report suggested a divorce was possible in the wake of the Carlos Ghosn scandal.